hello, can anyone tell me how streaming (directsound) can be done in real-time apps such as games? specifically, how do i handle the notification events? okay, so far, I have set up directsoundnotify, which will signal me to update the buffer content whenever certain position has been reached.. now the question is, how am I supposed to "capture" and handle the event objects? In one of the DirectX SDK examples, it shows handling of notification events using the WIN32 function MsgWaitForMultipleObjects(). However, the function will not return until one of the pre-defined events has been received, and that''s not ideal for games.. (I wish there is a way to just supply a callback function and handle it myself ) well, i''ve came up couple workarounds to this problem.. 1. go radical and stuff everything onto a static sound buffer 2. determine the current read postion in every game cycle.. (kinda risky) 3. set the expiration time in MsgWaitForMultipleObjects call... Help... can anyone show me the proper (elegant) way to handle a notification event? Thanks!!!!!!!

1) Use WaitForMultipleObjects with zero-timeout; that is, it returns immediately in any case. If it was successful (message was available), handle it. If not, proceed to next frame.

2) Create separate low-priority thread that handles exclusively sound buffering by constantly calling WaitForMultipleObjects.

In either case use fairly long buffers - a second or so - to avoid skipping if main process "halts" for a few moments. I''d recommend method #2, as it is fairly transparent, and requires no extra stuff in main...

quote: Original post by Hway

In either case use fairly long buffers - a second or so - to avoid skipping if main process "halts" for a few moments. I''d recommend method #2, as it is fairly transparent, and requires no extra stuff in main...

Hello,

thanks for the response!

I have decided to go with you suggestion, since I want
to encapsulate everything inside a "CMusic" class and
avoid messing around in WinMain...

However, another question came up while I was reading
the SDK docs.. just wondering if you can answer
it for me..

okay, now, let''s say i''m maintaining a buffer pointer
which is one second behind the play cursor. (The block
between my pointer and the play cursor contains data
that has already been played).

my pointer marks the beginning point where I want to
have the data updated.. (it implies that each update
will load one second worth of data onto the streaming
buffer)

Question 1:
when I lock the streaming buffer, which flag should
I specify in my lock() call?
DSBLOCK_FROMWRITECURSOR or DSBLOCK_ENTIREBUFFER?
(both flags seem inappropriate to me )

if i use DSBLOCK_ENTIREBUFFER flag, will it interrupt
the playing process?

Question 2:
maybe later...

just wanna clear up a few things in my previous post..

My concerns with the DSBLOCK_ENTIREBUFFER flag..


[Question 1]:

If i use DSBLOCK_ENTIREBUFFER to lock the entire buffer,
do i need to stop playing first? (which is not what i want,
since i'm doing streaming)

[Question 2]:

How do I maintain my buffer pointer? I think my buffer
pointer should probably be an offset into the buffer,
right? (in bytes, from start of buffer)
the pointer will also be used in each Lock() call.

Since the buffer is circular, I probably will need to check to
see if the end of buffer has reached...

here's the pseudo code:

DWORD buffer_ptr = 0; //start at beginning...

if(UPDATE_OCCURRED)
{
if(end is not reached)
{
buffer_ptr += 1_sec_worth_of_data;
}
else
{
buffer_ptr wraps around...
}
}

would you validate my logic for me?

[Question 3]:

What would you recommend for the data size for each
update?

1-sec worth of data for a 3-sec buffer is
good?


Thanks again!

Edited by - nobody321 on September 15, 2000 8:51:21 AM

Edited by - nobody321 on September 15, 2000 8:57:30 AM

Go check out the sound core in the Gauntlet Style Project section here. It contains streaming sound, using a seperate thread to handle messages. A perfect example of what you are trying to do.

Jim Adams

Reading the source codes now...

I''m fairly new to this site..

thanks for the pointer jim!